Choosing the refrigerant

This elaboration is about refrigerants for vapour compression systems (for gas cycles: What are refrigerants?). The vapour compression process is dominating most areas of refrigeration, especially those with large production numbers of systems.

• The refrigeration systems and appliances can be designed flexible and with low material and cost effort due to the low necessary mass flow.
• As the phase change is utilised, a large amount of energy can be transported per kg.
• The liquid refrigerant is easy to direct to the refrigerated rooms and appliances and the evaporated refrigerant is easy to be extracted, while the heat release and compression can be done at other places.
• Decoupling cold and hot side is an advantage for efficiency.

But before a refrigerant can be evaluated in terms of thermodynamics and efficiency in refrigeration applications, some other aspects need a closer look: material compatibility, availability of compatible lubricants, thermal and chemical stability and general availability of the fluid in sufficient amount at acceptable cost.